<% form_tag({:action => 'submit'}, :multipart => true) do %>
Problem: <%= select 'submission', 'problem_id', 
             	[['Specified in header','-1']] + 
		@problems.collect {|p| [p.full_name, p.id]},
		:selected => '-1' %>
File: <%= file_field_tag 'file' %>
<%= submit_tag 'Submit' %>
<% end %>
